The ability to determine current coordinates and motion parameters of movable objects (e.g., moving vehicles) using radio navigation systems is a long-standing problem and there are many well-known solutions representing a variety of techniques for such determination.
In one case, this determination can be accomplished using so-called range-difference location methods which are often used, for example, in different navigation satellite systems, such as the US Global Positioning System (GPS), the Russian GLONASS or European GALILEO, as are well-known. However, indoor GNSS signal reception, for example, within locations having deep mines, canyons or other such impenetrable formations, and/or dense urban high-rise housing developments is limited due to the restricted line-of-sight visibility of satellites in such navigation systems which results in a sharp drop in the effectiveness of such systems with respect to position determination.
Of course, to combat some of these challenges, there are well-known techniques to determine positions of vehicles that use pseudolite signals (i.e., pseudo-satellite signals) to achieve a certain level of navigation accuracy. For example, U.S. Pat. Nos. 6,449,558, 7,495,614, 7,859,462, and 8,675,561 describe different techniques for using pseudolite signals. Alternatively, there are also a number of well-known techniques (for example, as described in U.S. Pat. Nos. 8,738,035, and 6,449,558) that employ so-called hybrid positioning devices which utilize both GNSS signals and other different signals supplied by ground base stations to achieve position determination. An advantage of such systems is better coverage of the desired territory and improved position accuracy. However, such systems are, as a general matter, very complicated and expensive to deploy, and function as position-determining rather than data-transmitting thereby leading to low communication channel throughput. Further, these potential limitations are compounded in that the task of developing positioning-determining and data-transmitting systems for movable objects is quite critical in delivering certain desired levels of position determination and data communication.
To overcome some of the aforementioned limitations, there are a number of well-known positioning techniques that use Wi-Fi access points (hereinafter “AP”) and are based on measuring the strength of the received signal with a further comparison of the measured strength and the known spatial power distribution (e.g., the so-called fingerprinting positioning method). Such a fingerprinting position methodology is described, for example, in U.S. Pat. Nos. 7,515,578, 8,155,673, and 8,838,151. These technical solutions can be used for both position-determination and data transmission/reception of movable subscribers/customers via a Wi-Fi network. Some alternative well-known technical solutions also providing data transmission along with positioning tasks are also described, for example, in Unites States Patent Publication Nos. 2015/0087331, 2015/0099536, and 2015/0172863, respectively, wherein signals are transmitted through information channels of Wi-Fi networks. However, these known methods do not allow for obtaining highly accurate coordinate estimates (i.e., as measured in centimeter increments) and include a number of technical implementation difficulties that make deployment challenging.
Other known technical solutions for position determination (e.g., as described in U.S. Pat. Nos. 7,515,578, 7,916,661, and 8,155,673) employ certain information from ground maps, Wi-Fi AP distribution, and/or coverage zones and received signal intensity to specify a mobile user's position. Further, certain other known positioning devices (e.g., as described in United States Patent Publication Nos. 2012/0075145 and 2013/0093619) employ the phase difference of signals being received by selected spaced antennas to determine the position of a movable object.
U.S. Pat. No. 7,859,462 is another known positioning technique in which a rover's position is determined using a number of reference transmitters which generate and transmit in-phase navigation signals, which are received by a rover, and determining the delays associated with the received signals for the purpose of calculating the rover's position. However, this technique cannot be directly used for transmitting information between reference transmitters and a mobile receiver/rover due to low communication channel throughput.
Therefore, a need exists for an improved technique for determining the current coordinates and motion parameters of movable objects including when GNSS signal reception is impossible or deficient in providing a desired positioning accuracy.